With the increasing demand for cost-effective fuse elements used in high-end equipment, including new energy vehicles and rail transit systems, Ag-Cu composite strips have emerged as a promising alternative to pure Ag strips. While maintaining comparable electrical performance, these composite strips significantly reduce silver consumption. However, their service reliability in corrosive environments remains insufficiently investigated, which restricts their broader engineering applications. This study systematically compares the corrosion behavior and mechanisms of Ag-Cu strips with those of pure Ag and pure Cu strips using Tafel polarization tests, electrochemical impedance spectroscopy, 72-h salt spray tests, and multiscale characterization techniques. The results indicate the self-corrosion potential (Ecorr) follows the sequence Ag (− 0.268 V) > Cu (− 0.382 V) > Ag-Cu (− 0.408 V), whereas the self-corrosion current density (icorr) follows the order Ag-Cu (3.234 × 10−5 A cm−2) > Cu (2.501 × 10−5 A cm−2) > Ag (6.560 × 10−7 A cm−2). The primary cause of the corrosion performance differences lies in the electrode potential disparity between Ag and Cu, which induces severe interfacial galvanic corrosion. Interdigitated particles at the Ag/Cu interface create microchannels for corrosive media penetration, further intensifying synergistic effects of galvanic and pitting corrosion. Microstructural and chemical analyses indicate that Ag exhibits excellent corrosion resistance, while Cu forms a dual-layer corrosion product consisting of Cu2O and Cu2(OH)3Cl. In contrast, galvanic corrosion at the Ag-Cu interface accelerates corrosion, resulting in porous and loosely arranged corrosion products, which in turn lead to cavitation damage and interfacial degradation. The charge-transfer resistance (Rct) further validates the corrosion resistance hierarchy of Ag > Cu > Ag-Cu. This study provides the first systematic explanation of the dual-mechanism failure pathway governing the corrosion of Ag-Cu strips (galvanic corrosion coupled with pitting corrosion), thereby offering critical theoretical and technical guidance for interface design, process optimization, and the engineering application of cost-effective fusible materials.

Dual-Mechanism Corrosion Failure of Ag-Cu Composite Strips Driven by Interfacial Microstructure

期刊论文
发表日期：

2026年6月19日

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Shannan Zhang,
Tao Wang,
Guanxing Zhang,
Shengwei Li,
Xingxing Wang,
Jian Qin,
Junru Zuo,
Bao Wang,
Shu Chen

摘要

With the increasing demand for cost-effective fuse elements used in high-end equipment, including new energy vehicles and rail transit systems, Ag-Cu composite strips have emerged as a promising alternative to pure Ag strips. While maintaining comparable electrical performance, these composite strips significantly reduce silver consumption. However, their service reliability in corrosive environments remains insufficiently investigated, which restricts their broader engineering applications. This study systematically compares the corrosion behavior and mechanisms of Ag-Cu strips with those of pure Ag and pure Cu strips using Tafel polarization tests, electrochemical impedance spectroscopy, 72-h salt spray tests, and multiscale characterization techniques. The results indicate the self-corrosion potential (E_corr) follows the sequence Ag (− 0.268 V) > Cu (− 0.382 V) > Ag-Cu (− 0.408 V), whereas the self-corrosion current density (i_corr) follows the order Ag-Cu (3.234 × 10⁻⁵ A cm⁻²) > Cu (2.501 × 10⁻⁵ A cm⁻²) > Ag (6.560 × 10⁻⁷ A cm⁻²). The primary cause of the corrosion performance differences lies in the electrode potential disparity between Ag and Cu, which induces severe interfacial galvanic corrosion. Interdigitated particles at the Ag/Cu interface create microchannels for corrosive media penetration, further intensifying synergistic effects of galvanic and pitting corrosion. Microstructural and chemical analyses indicate that Ag exhibits excellent corrosion resistance, while Cu forms a dual-layer corrosion product consisting of Cu₂O and Cu₂(OH)₃Cl. In contrast, galvanic corrosion at the Ag-Cu interface accelerates corrosion, resulting in porous and loosely arranged corrosion products, which in turn lead to cavitation damage and interfacial degradation. The charge-transfer resistance (R_ct) further validates the corrosion resistance hierarchy of Ag > Cu > Ag-Cu. This study provides the first systematic explanation of the dual-mechanism failure pathway governing the corrosion of Ag-Cu strips (galvanic corrosion coupled with pitting corrosion), thereby offering critical theoretical and technical guidance for interface design, process optimization, and the engineering application of cost-effective fusible materials.